I’ve been using this stuff for decades and like it very much:

https://www.amazon.com/Bickmore-Bic...&hvtargid=pla-384918119428&psc=1

There are other saddle and tack products I have also used a long time, two of which are Leather New (a more penetrating cleaner and conditioner) and the Lexol brand of leather products. I would try Bick #4 first.